Gaming machines, such as slot machines, fruit machines, or poker machines, have in recent years become one of the more popular, exciting, and sophisticated wagering activities available at casinos and other gambling locations. At the same time, gaming machines have also become a source of greater revenue for gaming establishments. Thus, competition between manufacturers of gaming machines has intensified as competitors vie for business from gaming establishments. Additionally, gaming establishments compete among themselves to attract regular and repeat customers.
A gaming machine providing entertaining and enticing features for players would be highly desirable to attract both new and returning players to a gaming establishment. One way to encourage returning players is a player tracking or player loyalty program at a gaming establishment or network of related gaming establishments. Player loyalty programs reward incentives to players based on criteria, such as a number of visits to a casino, a number of games played, or other such criteria. For example, loyalty points may be assigned based on a criterion and redeemed for rewards such as discounts, free food or drink, lodging, transportation, entertainment, or other reward.
Being able to determine a location of certain players in a gaming establishment would also be highly desirable. Player location may be used to provide management of a gaming establishment with information to direct employees to bring a player his or her usual drink, food, and/or loyalty rewards, for example.
Player tracking may be facilitated by a gaming machine and/or by a reader, such as a card reader or a radio frequency identification (RFID) reader at or near the gaming machine. In some systems, for example, a player swipes his or her player card through a reader at a gaming machine before playing a game at that machine. In other systems, for example, an RFID reader detects an RFID tag embedded within a player card.
In an RFID system, the RFID reader includes a microchip and an antenna that transmits electromagnetic waves in an area around the location of the reader. The RFID tag on the player card also includes a microchip and antenna. When the electromagnetic waves from the reader impact the antenna on the tag, a magnetic field is formed. The RFID tag may be passive and draw power from the magnetic field to power the microchip. An active RFID tag is powered by a battery, for example. The microchip at the RFID tag modulates the waves received from the RFID reader and transmits the modulated waves back to the reader. The reader converts the received waves into digital data identifying the tag. The reader may then transmit data to a server to track player loyalty points and/or player location in a gaming establishment.
In gaming establishments utilizing RFID readers or similar systems, interference may result from multiple readers transmitting signals in close proximity to one another. Additionally, interference may result from multiple RFID tags responding to a single reader's transmission. Such interference may prevent scanning of a player's card or proper accumulation of player loyalty points. A malfunction or inaccuracy in the player loyalty or tracking system negatively impacts repeated customer business and positive reputation at a gaming establishment. Thus, accurate tracking of player loyalty points and/or player location is highly desirable.
An RFID-based player tracking system may include a plurality of readers or receivers, such as RFID readers, a plurality of player identification devices, and a server that may track player location and/or loyalty points. RFID readers transmit an “interrogation” signal to activate RFID tags in the vicinity of the reader. After transmission, the RFID readers “listen” or wait to receive response signals from RFID tags in response to the interrogation signal. When an RFID reader receives a response, data conveyed by the response is relayed to the server for further processing. The server may use the data along with information regarding an identity and location of the RFID reader to determine a location of the RFID tag. The RFID tag may be associated with a particular player profile. Once the identity and location of the player are determined, an action such as initiating a player loyalty session or special attraction mode on a nearby gaming machine may be activated by the server. Additionally, attention may be directed to the player at the location by the gaming establishment.
RFID tags may be implemented as read-write devices, capable of receiving and storing information sent by a nearby RFID reader. Thus, the RFID tag may be used to store information amount a player or holder, such as name, refreshment preferences, access level, and other information. Such information stored at the RFID tag may then be accessible by RFID readers. Information transmitted between an RFID reader and an RFID tag may be encrypted.
RFID readers may be integrated into gaming machines or other gaming systems and/or positioned throughout the floor of the gaming establishment (e.g., a casino). In a crowded environment with many RFID readers, RFID readers may interfere with each other through transmission and/or receipt of signals. Interference, often referred to as reader collision, may occur when two or more RFID readers within range of each other transmit interrogation signals at approximately the same time. Simultaneous transmission may result in erratic reading of RFID tags, reduced reading range, or even an inability to read tags.
Distance between RFID readers that exposes the readers to reader collision varies (from less than a foot to hundreds of feet, for example) depending on factors such as transmitter power, receiver sensitivity, RFID reader frequency, and physical characteristics of transceiver antenna and RFID tags in the area. Environmental factors, such as metal structures that may conduct or reflect radio signals, may also influence a potential for mutual interference.
Systems, such as U.S. Patent Publication No. 2003/0036425A1 to Kaminkow et al, attempt to address reader collision in two primary ways: (1) by shaping an active volume of the RFID reader through use of shielding around RFID reader antenna and/or by varying transmitter power and (2) by using the location manager to control operation of the RFID readers. However, both methods have drawbacks.
Shaping the active volume of an RFID reader by shielding the RFID reader antenna may be somewhat effective in reducing the interference between the RFID readers housed in adjacent gaming systems. However, shielding does not reduce interference between RFID readers housed in gaming machines that face each other from opposing banks of machines. Reducing the power of the transmitters may help reduce interference to a limited extent but also reduces an ability of an interrogation signal to penetrate to an RFID tag held in a wallet, purse or pocket, for example. Reducing power of transmitters to a point that eliminates reader collision may also create blind spots in a system's coverage of a gaming environment, such as a casino floor.
Additionally, the shielding material used to shape the active volume of the RFID reader may also have an undesirable effect of de-tuning the RFID antenna. De-tuning the antenna results in reduced performance of the RFID reader.
Current RFID readers operate autonomously with respect to each other and communicate only with a single, centralized location manager responsible for managing the operation of all RFID readers on a property. Such a system may be managing the operation of hundreds or even thousands of RFID readers, as well as processing data produced by the readers. Extensive management places a heavy burden on current tracking systems. Additionally, a complex network associated with current systems includes inherent delays that reduce responsiveness of the system and impair the ability of the system to process a large number of RFID tags in a timely manner.
Attempts have been made to overcome the difficulty in reading multiple RFID tags in a given area. In one method, a command response protocol is used to interrogate RFID tags with specific identities or groups of identities using a tree algorithm. However, this and other methods are susceptible to blocking efforts, such as denial of service attacks by specially built RFID tags, such as those developed by RSA Laboratories, that respond to all interrogations regardless of the identifier.
Therefore, a system and method that overcome the shortcomings associated with current systems would be highly desirable. A system and method that improve management of RFID devices in a gaming environment would be highly desirable. A system and method that help to avoid deliberate interference, such as denial of service devices, would also be highly desirable.
Thus, there is a need for an improved system and method for synchronizing RFID readers in close proximity in a gaming environment.